PD72042B_15 Datasheet, PDF (11/92 Pages) Renesas Technology Corp – LSI DEVICE FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL

µPD72042B
2.2 IEBus COMMUNICATION PROTOCOL
The IEBus is outlined below.
• Communication method: Half duplex asynchronous communication
• Multi-master method
All units connected to the IEBus can transmit data to every other connected unit.
• Broadcast function (one-unit-to-multiple-units communication)
Group broadcast : Broadcast to a specific group of units
General broadcast : Broadcast to all units
• Two modes, each offering different transmission speeds, can be selected.
Mode 0
Mode 1
fX = 6 MHz
Approx. 3.9 Kbps
Approx. 17 Kbps
fX = 6.29 MHz
Approx. 4.1 Kbps
Approx. 18 Kbps
Maximum number of bytes
transmitted (bytes/frame)
16
32
• Access control: Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Bus mastership priority is as follows:
1 Broadcast takes priority over ordinary communication (one-unit-to-one-unit communication).
2 Units having lower master addresses have a higher priority.
• Communication scale
Number of units
Cable length
Load capacity
Terminating resistance
: 50 max
: 150 m max (when twisted-pair cable is used <resistance 0.1 Ω/m or less>)
: 8000 pF max <between BUS- and BUS+>, fX = 6 MHz
7100 pF max <between BUS- and BUS+>, fX = 6.29 MHz
: 120 Ω
Caution For the µPD72042B, as a protective resistance, connect a 180-Ω resistor in series with the BUS–
and BUS+ pins.
Data Sheet S13990EJ3V0DS
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